Catalytic decomposition of hydrogen peroxide on transition metal and lanthanide oxides

Removal of NOX Using Hydrogen Peroxide Vapor over Fe/TiO2 Catalysts and an Absorption Technique

“…The significant increase of NO oxidation efficiency in the presence of catalyst could be attributed to the activated species produced from catalytic decomposition of H 2 O 2 vapor. The catalytic mechanism of a H 2 O 2 molecule over TiO 2 is analogous to the Fenton-type mechanism, and the reaction pathways can be described by the following equations [13,15]:…”

“…TiO 2 is considered to be an ideal catalyst for the removal of air pollutants-including NO X -due to its excellent chemical stability, low cost, and nontoxicity toward both humans and the environment [12]. Recent studies have proven that H 2 O 2 can act both as an oxidant and as a reductant via a redox path of Ti 3+ /Ti 4+ when the decomposition reaction of a H 2 O 2 molecule over a TiO 2 surface occurs [13]. It should be noted that defective surface sites, especially for the oxygen vacancies, play a significant role in the decomposition of H 2 O 2 [14].…”

Surface reactivity of hydroxyl radicals formed upon catalytic decomposition of H2O2 on ZrO2

“…Although the rate constants for the heterogeneous reactions (R8) and (R9) (k 8 and k 9 ) have not been experimentally determined, it is reasonable to assume that these reactions should be fast. Hence, (R8) and (R9) cannot be regarded as the ratedetermining steps for the overall process [8,16,19]. Therefore, k 8 and k 9 are fixed at 1 × 10 8 M −1 s −1 (between their rate constants of 2.7 × 10 7 M −1 s −1 and 1.1 × 10 9 M −1 s −1 in homogeneous system) [30,31].…”

“…The radiolysis products of water are e aq − , H • , HO • , H 2 , H 3 O + and H 2 O 2 [5]. As a stable molecular oxidizing product, the reactivity of H 2 O 2 in both homogeneous and heterogeneous systems is intriguing and has been investigated in nuclear technology as well as in other fields such as catalysis, medical sciences and environmental chemistry [6][7][8][9][10]. Nevertheless, given the complexity of heterogeneous systems, the knowledge of the surface reactivity of H 2 O 2 is still quite limited.…”

Application of reactivity descriptors to the catalytic decomposition of hydrogen peroxide at oxide surfaces

“…Relaxing this geometry leads to a rearrangement of the structure which spontaneously forms 2 adsorbed HO radicals. This suggests that the H atom transfer behaves differently from the other oxides in terms of kinetic parameters for H 2 O 2 decomposition and HO • formation dynamics[55]. A contribution from the Fenton reaction for the experimentally measured energy barrier has been proposed to account for the differences.…”